Publius makes an an argument that the realities of votes and politics require that the Democrats keep Joe Lieberman in his chairmanship on the Homeland Security Committee.
While his arguments are logical, they are also wrong. They are predicated on the idea that he generally votes with the Dems, and this is really not true. He votes with the Dems when it does not matter, so he voted against Alito, and voted for Cloture.
If he is the 60th vote for cloture, he will not vote for cloture, because as he has already made clear, he is intent on extracting vengeance against a Democratic party that he feels has betrayed him.
As to whether you allow him to caucus with the Dems, that’s their business, but he should not be chairman of anything significant, particularly homeland security, which has been politicized, and needs to be de-Bushified.
Any authority that he is granted will merely serve his petty vendetta.